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Epidemiology of breast cancer

Epidemiology of breast cancer

Read Breast Cancer first.

Genes and breast cancer

The genetically defined group of women with BRCA-1 or BRCA-2 identified to carry lifetime risk of as high as 80%. These genes function in cells in a variety of ways such as

  1. Repair of damages DNA
  2. Cell-cycle regulation
  3. Transcriptional regulation
  4. Remodeling of chromatin in cells. Chromatin are the gene carrying vehicles in all cells
  5. BRCA-2 is involved primarily in DNA recombination and repair

The reason why these genes predispose primarily to breast cancers remains unknown. BRCA1 and BRCA2 genes can be carried and passed to children by men as well as by women. A drug tamoxifen has been shown to reduce the risk of contralateral breast cancer by about 50% in both BRCA1 and BRCA2 carriers.

The characteristics of BRCA1 and BRCA2 genes

HER2 genes

Another gene, HER2 presents with its protein over expression in 20% of newly diagnosed breast cancers. HER2 stands for Human Epidermal growth factor Receptor 2.

HER2 gene positive breast cancer is associated with a more aggressive clinical course and decreased survival time compared to tumors with normal levels of HER2. Each normal breast cell contains copies of the HER2 gene found in the DNA of the cell. HER2 contains information that helps to make HER2 proteins.

The HER2 protein is the HER2 receptor found on the surface of some normal cells in the body. The proteins help send growth signals from outside the cell to the inside of the cell and pass the message for cells to grow and divide.

In HER2+ breast cancer, the cancer cells have an abnormally high number of HER2 genes per cell. When this happens, too much HER2 protein appears on the surface of these cancer cells. This is called HER2 protein overexpression. This causes the cells to grow and divide more aggressively. This contributes to growth autonomy and genomic instability where the cells growing hev no control at all.
Symptoms of breast cancer

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